Volume controlled hydrodynamic separator for stormwater treatment

ABSTRACT

A method, system, and apparatus directed to an innovative approach for the treatment of stormwater utilizing hydrodynamic separator assembly designed to maximize flow movement for more efficient sediment removal and maximize clearance space within assembly to facilitate cleaning and increase storage capacity of trash, debris, and sediment. In particular, the described hydrodynamic separator is an improvement over other hydrodynamic separators known in the art with the inclusion of one or more down pipes which siphon water from the lower portion of the sump chamber. The inclusion of down pipes allows for an improved control of the velocity of the water flow through the device by distributing flow into more than one path.

The present application is a Continuation-in-Part of U.S. patentapplication Ser. No. 16/505,275 filed on Jul. 8, 2019, which is aContinuation of U.S. patent application Ser. No. 15/700,149, filed onSep. 10, 2017, now U.S. Pat. No. 10,344,466 issued on Jul. 9, 2019.

BACKGROUND OF THE INVENTION Field of the Invention

The embodiments of the present technology relate in general to advancedsediment removal devices based on principles of hydrodynamic and gravityseparation. More specifically, a hydrodynamic separator to removesediments and other pollutants from polluted stormwater runoff andpolluted water sources. The hydrodynamic separator is designed to reducevelocity and maximize flow path within a settling chamber of minimalsize to maximize performance and feasibility. The embodiments describedin this application demonstrate an improvement over other hydrodynamicseparators known in the art with the inclusion of one or more down pipeswhich siphon water from the lower portion of the sump chamber. Theinclusion of down pipes allows for an improved control of the velocityof the water flow through the device by distributing flow into more thanone path. The hydrodynamic separator is generally installed subsurfacewithin the drainage infrastructure of various private and publicdrainage systems.

Background and Prior Art

Water treatment systems have been in existence for many years. Thesesystems treat stormwater surface runoff or other polluted water.Stormwater runoff is of concern for two main reasons: i. volume and flowrate, and ii. pollution and contamination. The volume and flow rate ofstormwater runoff is a concern because large volumes and high flow ratescan cause erosion and flooding. Pollution and contamination ofstormwater runoff is a concern because stormwater runoff flows into ourrivers, streams, lakes, wetlands, and/or oceans. Pollution andcontamination carried by stormwater runoff into such bodies of water canhave significant adverse effects on the health of ecosystems.

The Clean Water Act of 1972 enacted laws to improve water infrastructureand quality. Sources of water pollution have been divided into twocategories: point source and non-point source. Point sources includewastewater and industrial waste. Point sources are readily identifiable,and direct measures can be taken to mitigate them. Non-point sources aremore difficult to identify. Stormwater runoff is the major contributorto non-point source pollution. Studies have revealed that contaminatedstormwater runoff is the leading cause of pollution to our waterways. Aswe build houses, buildings, parking lots, roads, and other imperviousareas, we increase the amount of water that runs into our stormwaterconveyance systems and eventually flows into rivers, lakes, streams,wetlands, and/or oceans. As more land becomes impervious, less rainseeps into the ground, resulting in less groundwater recharge and highervelocity flows, which cause erosion and increased pollution levels ofwatery environments.

Numerous sources introduce pollutants into stormwater runoff Sedimentsfrom hillsides and other natural areas exposed during construction andother human activities are one source of such pollutants. When land isstripped of vegetation, stormwater runoff erodes the exposed land andcarries it into storm drains. Trash and other debris dropped on theground are also carried into storm drains by stormwater runoff Anothersource of pollutants includes leaves and grass clippings fromlandscaping activities that accumulate on hardscape areas and do notdecompose back into the ground, but flow into storm drains and collectin huge amounts in lakes and streams. These organic substances leach outlarge amounts of nutrients as they decompose and cause large algaeblooms, which deplete dissolved oxygen levels in marine environments andresult in expansive marine dead zones. Unnatural stormwater pollutingnutrients include nitrogen, phosphorus, and ammonia that come fromresidential and agricultural fertilizers.

Heavy metals that come from numerous sources are harmful to fish,wildlife, and humans. Many of our waterways are no longer safe forswimming or fishing due to heavy metals introduced by stormwater runoff.Heavy metals include zinc, copper, lead, mercury, cadmium and selenium.These metals come from vehicle tires and brake pads, paints, galvanizedroofs and fences, industrial activities, mining, recycling centers, etc.Hydrocarbons are also of concern and include oils, gas, and grease.These pollutants come from leaky vehicles and other heavy equipment thatuse hydraulic fluid, brake fluid, diesel, gasoline, motor oil, and otherhydrocarbon based fluids. Bacteria and pesticides are additional harmfulpollutants carried into waterways by stormwater runoff.

Over the last 20 years, the Environmental Protection Agency (EPA) hasbeen monitoring the pollutant concentrations in most streams, rivers,and lakes in the United States. Over 50% of waterways in the UnitedStates are impaired by one of more of the above-mentioned pollutants. Aspart of the EPA Phase 1 and Phase 2 National Pollutant DischargeElimination Systems, permitting requirements intended to controlindustrial and nonindustrial development activities have beenimplemented. Phase 1 was initiated in 1997 and Phase 2 was initiated in2003. While there are many requirements for these permits, the mainrequirements focus on pollution source control, pollution control duringconstruction, and post construction pollution control. Post constructioncontrol mandates that any new land development or redevelopmentactivities incorporate methods and solutions that both control increasedflows of surface water runoff from the site and decrease (filter out)the concentration of pollutants off the site. These requirements arecommonly known as quantity and quality control. Another part of theserequirements is for existing publicly owned developed areas to retrofitthe existing drainage infrastructure with quality and quantity controlmethods and technologies that decrease the amount of surface waterrunoff and pollutant concentrations therein.

One approach to treat stormwater known in the art is separation orsedimentation of materials that are not neutrally buoyant, as anexample, particles that are heavier and trash and oils that are lighter.Stormwater treatment devices that provide this method of treatment arecalled hydrodynamic separators. A hydrodynamic separator, or settlinghydrodynamic separator, controls the flow of water by reducing incomingvelocities and maximizing flow of the flow path which allows trash,debris, and total suspended solids (TSS), floatables and oils to settleout of the stormwater and remain contained within the hydrodynamicseparator for later removal.

SUMMARY OF THE INVENTION

The present invention accomplishes the above listed objectives by usinga uniquely designed hydrodynamic separator including a flow splitterwhich redirects the flow of water upon entering the sump chamber fromthe inlet pipe. The flow splitter in combination with the oil-floatablesskimmer minimizes the velocity of inflowing water and redirects it awayfrom the center of the structure, which is generally round, and thenalong the structure's perimeter walls in two directions. Water flowsalong the walls and toward the oil-floatables skimmer on both sides. Asthese flows come in contact with the skimmer the flows continue alongthe skimmer wall back toward the center where the two flow paths flowinto each other. At this point the flow paths are forced back toward theinlet pipe from which they came. The two flow paths make a completecircle on the influent side of the oil-floatables skimmer. This createsa dual swirl action within the system and maximizes the flow path whilekeeping velocities low within the hydrodynamic separator, allowing forefficient capture and retention of trash, debris, and total suspendedsolids (TSS). Directing flows, containing sediments, especially finersediment, back under the inlet pipe, which is as far away from theoutlet pipe as possible, maximizes the ability of the system to captureand retain the finer sediments.

The outlet weir also plays a significant role in the system'sperformance. As with inlet velocities, outlet or exit velocities canalso have a major impact on a systems overall effectiveness. Duringproduct development, different configurations were tested such aswithout an outlet weir, a shorter outlet weir and a taller outlet weir.A 9-inch tall outlet weir, measured from the outlet pipe invert provedto provide optimal performance. All weir configurations proved to bemore effective than no outlet weir. In general, as water exits astructure and back into a pipe the velocity from the structure to thepipe quickly increases due the contraction of area into the pipe. Thiscontraction creates a vacuum effect within the structure and can pullsediments out of the system that would have settled given more time anda condition of less velocity. To overcome this challenge, an outlet weiris placed across the outlet pipe. The outlet weir width is maximizedwithin the system in order to spread the flow over it evenly. Because ofthe width of the weir is substantially wider than the pipe, the velocityof flow over the weir is minimized in a laminar fashion. This in turnincreases the time particulates have to settle out on the effluent sideof the oil-floatables skimmer. The weir also raises the water level inthe system thus increasing the volume of water. The greater the volumeof water within the system the more retention time. Studies have shownincreased retention time also increases performance in particulateremoval.

The outlet weir component is further enhanced with the inclusion of oneor more down pipes which siphon a portion of water from the lowerportion of the sump chamber. The inclusion of down pipes allows for animproved control of the velocity of the water flow through the device bydistributing flow in two different directions. A portion of the waterflows upward and over the outlet weir and the remaining portion flowsdown to enter the down pipes and thus bypasses the outlet weir crest.The vertical distribution of flow reduces velocity hot spots which canreduce performance.

The present invention solves well know problems in the art such as shortcircuiting, minimal flow paths, minimal velocity reductions, inabilityto capture and retain finer sediments, floatables and oils/hydrocarbons.Other systems that employ velocity reduction and flow path maximizationtechniques do so without splitting the flow in two separate directions.This singular flow path has limited effectiveness as the velocity canonly be reduced by the width of the structure in relation to inletvelocity. For example, a 2-foot pipe entering a 4-foot wide hydrodynamicseparator can only reduce the velocity by half its inlet rate if flowdistribution is perfectly even, which is known as laminar flow. A systemthat maximizes the flow path by directing all flows in one directiondoes not reduce the velocity of inflowing water thus minimizing itsability to capture finer particulates. Since the present inventionsplits the influent flow velocity in half its performance in capturingfiner particulates is increased.

Another problem with other systems is the amount of flow pathmaximization. Generally, the inlet pipe is on the opposite side of thecylindrical structure from the outlet pipe. As water is directed alongone wall it travels half the circumference of structures perimeterbefore nearing the outlet pipe. The present invention directs flows backtowards the inlet side of the system. The flow then will have to stilltravel, at a lower elevation in the system, back along the perimeterwalls of the structure along both sides back towards the outlet pipe.Thus, water must travel in two full revolutions before nearing theoutlet pipe, once again maximizing flow path while keeping velocitiesminimized.

Maintenance access is a major concern which is related to the design ofthe system. Other systems have very limited access to the sump chamberwhere sediment is collected. These systems generally need to bemaintained by finish surface without access into the system. Entry intothe system requires confined space which adds a lot of time and cost tothe required maintenance. Other systems have horizontally extendingdecks below the inlet and outlet that extend across the majority of thearea of the cylindrical structure. This makes access to the sump chamberbelow limited. Most other systems have a single access port near thecenter of the structure for the insertion of the vacuum hose to removecaptured sediments and other pollutants. For example, one systemmarketed under the name StormCeptor, has a system with a 6-foot diameterstructure yet only a 1-foot diameter maintenance access port. Othersystems have similar configurations. A few have access that is almosthalf the area (50%) of the structure which is industry leading. Thedesign of the present invention allows for more than 70% unimpededaccess to the sump chamber below. This allows for easy visualobservation, from finish surface to the sump chamber below to measureand ensure all sediments have been removed. Other systems cannot bevisually inspected and because access into the sump chamber below is sorestricted that only a portion of the sediment captured is ever removed.Generally, the sediment will be evenly distributed on the floor of thesump chamber. If the vacuum hose can only be inserted through a smallport in the middle, there is no way for it to remove all the sedimentnot located directly under the access port. Several reports haveverified that the sediment captured in hydrodynamic separators willbecome compacted and hard after being stored for several months. Becausea majority of the sediments cannot be removed from other separators, itssediment storage capacity after initial installation is severelyreduced. As such the required maintenance interval on these systems isdrastically increased which increases the cost and frequency to maintainthese systems.

Unlike other hydrodynamic separators known in the art, the presentedinvention is an innovative method utilizing the combination of the flowsplitter, oil-floatables skimmer, down pipes, and outlet weir. The sumpchamber has minimum obstructions which include only the flow splitter,an oil-floatables skimmer, and an outlet weir. The simplicity of adesign with few parts provides a sustainable solution by reducing theamount of materials required for the hydrodynamic separator to functionoptimally. Fewer materials and parts reduce the cost of production.

A preferred embodiment of installation of the hydrodynamic separator iswithin a drainage infrastructure as it can easily be installed inlinewith existing pipes.

The hydrodynamic separator can range in size from 2 feet in diameter upto 100 feet in diameter but generally ranges from 4 feet to 14 feet indiameter.

In some embodiments, more than one inlet and outlet pipe may beintegrated into the hydrodynamic separator at different angles to allowfor installation in various stormdrain arrangements.

The hydrodynamic separator is capable of greater than 80% removal oftotal suspended solids based on a typical particle size distributionfound in stormwater runoff by maximizing the flow path and therebysignificantly reducing the velocity of stormwater through thehydrodynamic separator. Notably, trash, debris and floatables are nottrapped in the flow splitter as it enters the sump chamber from theinlet pipe because the flow splitter has openings on both sides,allowing for stormwater and floatables to transition to the open area onthe influent side of the oil-floatables skimmer. Stormwater is furthertreated by the oil-floatables skimmer, which due to the slowed velocity,results in up to ninety-nine percent retention of free floating oils andgrease.

During periods of high flow, the hydrodynamic separator will continue totreat the incoming stormwater. The flow splitter height is designed tosplit incoming flows up to a certain flow rate. At higher flow rates thewater may pass over the top of the flow splitter's walls to reduce headloss. The oil-floatables skimmer is designed at a height with its topabove the highest possible water level, hydraulic grade line, so that nofloatables or oils captured will be lost during these high flows. Allflows must pass under the oil-floatables skimmer even during periods ofhigh flow. The outlet weir only extends above the outlet pipe invert toa minimal distance allowing high flows to pass over it withoutgenerating significant head loss.

OBJECTIVES OF THE INVENTION

It is an objective of the invention to use flow weirs to direct waterflow by impeding normal water flow through a drainage structure.

Further, it is the objective to reduce the rate of velocity through astormwater treatment system with the weirs by changing the naturaldirection of the flow path. Down pipes as described herein furtherfacilitate control of the velocity of water flow. This allows forsignificantly increased rates of sediment precipitation.

In preferred embodiments, it is an objective of the invention to utilizeflow weirs of at least one flow splitter, oil-floatables skimmer and atleast one outlet weir where water is treated by each of these flow weirsto remove fine sediment, oils and grease, trash and other debris.

It is an objective of this invention to use a flow splitter near theinlet pipe to create a swirling flow path on the inlet side of the oilskimmer to drastically reduce velocity and extend flow path length.

It is an objective of this invention to use an outlet weir to createlaminar flow over the weir to again reduce the velocity of the water forfurther settling before it exits the outlet pipe.

It is an objective of this invention to maximize access to the floor ofthe hydrodynamic separator to facilitate cleaning.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. Illustrates a side-view, cut-out schematic of the hydrodynamicseparator, in accordance with one embodiment.

FIG. 1A. Illustrates a side-view, cut-out schematic of the hydrodynamicseparator with drain pipes, in accordance with one embodiment.

FIG. 2. Illustrates an isometric-view, cut-out schematic of thehydrodynamic separator oriented toward the outlet pipe, in accordancewith one embodiment.

FIG. 2A. Illustrates a partial, isometric-view, cut-out schematic of analternate embodiment of the hydrodynamic separator with drain pipes andis oriented toward the outlet pipe, in accordance with one embodiment.

FIG. 2B. Illustrates a more detailed isometric-view, cut-out schematicof an alternate embodiment of the hydrodynamic separator with drainpipes affixed to an outlet weir and is oriented toward the outlet pipe,in accordance with one embodiment.

FIG. 3. Illustrates an isometric-view, cut-out schematic of thehydrodynamic separator oriented toward the inlet pipe, in accordancewith one embodiment.

FIG. 3A. Illustrates a partial, isometric-view, cut-out schematic of analternate embodiment of the hydrodynamic separator with one drain pipeand is oriented toward the inlet pipe, in accordance with oneembodiment.

FIG. 3B. Illustrates a more detailed isometric-view, cut-out schematicof an alternate embodiment of the hydrodynamic separator oriented towardthe inlet pipe, in accordance with one embodiment.

FIG. 4. Illustrates a top-view of the hydrodynamic separator inoperation showing the flow path at the surface water level, inaccordance with one embodiment.

FIG. 5. Illustrates a side-view, cut-out schematic of the hydrodynamicseparator in operation showing the flow path at the surface water leveland lower portion of the water column, in accordance with oneembodiment.

FIG. 6. Illustrates a top-view of the sump chamber, in accordance withone embodiment.

FIG. 6A. Illustrates a top-view of the sump chamber in operation showingthe flow path at a lower portion of the water column, in accordance withone embodiment.

FIG. 6B. Illustrates a simple, top-view of the sump chamber inconnection with upstream and downstream elements of the hydrodynamicseparator, in accordance with one embodiment.

FIG. 7. Illustrates an isometric view of a flow splitter and void areasallowing for water to flow through the system, in accordance with oneembodiment.

FIG. 8. Illustrates an isometric view of an outlet weir, in accordancewith one embodiment.

FIG. 8A. Illustrates a partial isometric view of another embodiment ofthe outlet weir with drain pipes, in accordance with one embodiment.

FIG. 9. Illustrates an isometric view of an oil-floatables skimmer, inaccordance with one embodiment.

FIG. 9A. Illustrates an isometric view of a segmented oil-floatablesskimmer, in accordance with one embodiment.

FIG. 10. Illustrates a side-view, cut-out schematic of the sump chamberduring cleaning on the inlet side of the hydrodynamic separator, inaccordance with one embodiment.

FIG. 11. Illustrates a side-view, cut-out schematic of the sump chamberduring cleaning on the outlet side of the hydrodynamic separator, inaccordance with one embodiment.

DETAILED DESCRIPTION OF THE INVENTION

After reading this description it will become apparent to one skilled inthe art how to implement the invention in various alternativeembodiments and alternative applications. However, all the variousembodiments of the present invention will not be described herein. It isunderstood that the embodiments presented here are presented by way ofan example only, and not limitation. As such, this detailed descriptionof various alternative embodiments should not be construed to limit thescope or breadth of the present invention as set forth below.

The present invention provides an improved hydrodynamic separator 10 forstormwater treatment designed to maximize flow movement for moreefficient sediment removal from stormwater and to maximize clearancespace within the sump chamber to facilitate cleaning and increasestorage capacity of trash, debris, and sediment.

In some embodiments, configurations of said invention can be customizeddepending on site needs, government regulations, and consumerpreference. The hydrodynamic separator utilizes flow weirs to maximizeflow movement and slow water flow rate within the hydrodynamicseparator. The interchange of the type and number of weirs depends onthe configuration installed. Flow weirs may be selected from a groupconsisting of: flow splitter(s), oil-floatables skimmer, sedimentbaffles, v-notch weirs, outlet weir(s) or other weirs that alter flowcharacteristics of water through the hydrodynamic separator. Other flowweirs, including bypass weirs and low flow diversion weirs, for example,have been contemplated at the time of invention and may be includedand/or substituted in the invention to manage water velocity and improvesediment and floatable trash and debris removal. The flow weirs merelyserve to support the primary functions of the invention without equatingto an overall change in the function and purpose of the hydrodynamicseparator.

In a preferred embodiment, the hydrodynamic separator is a substantiallycircular or alternatively a cylindrical chamber. Alternate embodimentsof the hydrodynamic separator may allow for non-uniform configurations,for example a bowed shape, squares or rectangles. The hydrodynamicseparator comprises a top 11 and the top having one or more openings 13which can be covered via an access riser(s) 7 and/or manhole covers 8and a solid bottom 12. The hydrodynamic separator 10 has at least oneinlet pipe 1 and one outlet pipe 6 located above the sump chamber 3. Thesump chamber 3 is defined as the area below the inlet pipe invert 1 awithin the hydrodynamic separator 10 which holds water and allows forseparation.

Within the hydrodynamic separator 10, adjacent to the inlet pipe 1 andoutlet pipe 6, there are three removably mounted flow weirs affixed tothe hydrodynamic separator's 10 sides walls 14. These flow weirs serveto alter the flow of stormwater through the hydrodynamic separator 10 toenhance performance in removing sediments, particulates, trash, andoils. In preferred embodiments, the flow weirs are selected from a groupconsisting of: a flow splitter 2, an oil-floatables skimmer 4, and anoutlet weir 5.

The flow path between the flow splitter 2 to the oil-floatables skimmer4 is maximized by splitting and slowing the influent flows from theinlet pipe 1 and directing the flows along the hydrodynamic separatorwalls 14 toward the oil-floatables skimmer 4 at the point where theoil-floatables skimmer 4 connects to the hydrodynamic separator chamberwalls 14 and inward along oil-floatables skimmer 4 toward the center ofthe sump chamber 3 where the flows that were split meet back up and arepushed back toward the flow splitter 2 and inlet pipe 1 from which itcame thus maximizing the flow path by taking it in a full circle in twosplit and opposite directions. This flow path between the flow splitter2, oil skimmer 4, and the inlet pipe 1 can be traced via the arrows ofthe swirling flow from the inlet on the surface 30.

The oil-floatables skimmer 4, which is operative to isolate hydrocarbonsfrom water for later removal, further serves as a barrier preventingfloatable trash and large floatable debris from moving from the inletpipe 1 side of the sump chamber 3 to the outlet pipe 6 side of the sumpchamber 3 as water must pass under the oil-floatables skimmer 4. Sincethe oil-floatables skimmer 4 is connected to the hydrodynamicseparator's walls 14 at its widest point the flow under theoil-floatables skimmer 4 is laminar thereby minimizing velocities andproviding greater time for settling of particulate matter such assediments and retaining floatables which are stored on the inlet pipe 1side of the sump chamber 3 until the sump chamber 3 is accessed via themanhole cover 8, access riser 7 and through the top opening 13 forcleaning, using, in some embodiments, a vacuum hose 9. Theoil-floatables skimmer 4 has been independently tested by a third-partylab. Their results demonstrate the oil-floatables skimmer 4 installedwithin the hydrodynamic separator 10 is capable of removing andretaining up to ninety-nine percent of oils and grease (Good HarbourLaboratories, June 2017).

The third component for controlling the flow of water is the outlet weir5. The outlet weir 5 widens the horizontal plane in which water mustflow over to get to the outlet pipe 6. The longer horizontal planespreads out the flow in a laminar fashion thereby reducing the velocityin the hydrodynamic separator 10 in the area of the sump chamber 3 onthe effluent side of the oil-floatables skimmer 4 providing one lastopportunity for finer sediment to settle to the bottom of the sumpchamber 3 before exiting the hydrodynamic separator 10 via the outletpipe 6. This flow path over the outlet weir 5 is demonstrated by thearrows depicting laminar flow over the outlet weir 31. The outlet weir 5is further enhanced with the inclusion of one or more down pipes 26which siphon a portion of water from the lower portion of the sumpchamber. The inclusion of down pipes 26 allows for an improved controlof the velocity of the water flow through the hydrodynamic separator 10by distributing flow in two different directions. A portion of the waterflows upward and over the outlet weir 5 and the remaining portion flowsdown to enter the down pipes 26 and thus bypasses the outlet weir crest.The vertical distribution of flow reduces velocity hot spots which canreduce performance. The dual flow path design is optimized so thatperiods of low flow, all or most of the flow travels through the downpipes 26. During periods of moderate flow conditions the flow is evenlydistributed over the outlet weir 5 and through the down pipes 26. Duringperiods of high flow conditions, most or all of the flow goes over theoutlet weir 5.

FIG. 1 presents an embodiment contemplated by the inventor at the timeof filing wherein the hydrodynamic separator 10 hydrodynamic separatorincludes the elements of: a top 11, a top opening 13, and a bottom 12,side walls 14, a sump chamber 3 defined as the area in the hydrodynamicseparator 10 below an inlet pipe 1, an inlet pipe invert 1 a, a flowsplitter 2, an oil-floatables skimmer 4, an outlet weir 5, an outletpipe 6, and an access riser 7 and manhole cover 8.

FIG. 1A presents a preferred embodiment with a drain pipe 26 affixed tothe outlet weir 5. Other elements depicted reflect those in FIG. 1,including: the hydrodynamic separator 10 hydrodynamic separator includesthe elements of: a top 11, a top opening 13, and a bottom 12, side walls14, a sump chamber 3 defined as the area in the hydrodynamic separator10 below an inlet pipe 1, a flow splitter 2, an oil-floatables skimmer4, an outlet weir 5, an outlet pipe 6, and an access riser 7 and manholecover 8.

FIG. 2 is similar to FIG. 1 with the exception of presenting anorientation towards the outlet pipe 6 to demonstrate a near frontal-viewof the flow splitter 2. Other elements of the hydrodynamic separator 10depicted include: a top 11 and a bottom 12 and top opening 13, a sumpchamber 3, an inlet pipe 1, a flow splitter 2, an oil-floatables skimmer4, an outlet weir 5, an outlet pipe invert 6 a, and an access riser 7and manhole cover 8.

FIG. 2A is similar to FIG. 2 however, it includes the addition of onedown pipe 26 affixed below the outlet weir 5 through the outlet weirorifice control hole 24. The orientation of the figure is towards theoutlet pipe 6 to demonstrate a near frontal-view of the flow splitter 2.Other elements of the hydrodynamic separator 10 depicted include: a top11 and a bottom 12 and top opening 13, a sump chamber 3, an inlet pipe1, a flow splitter 2, an alternate embodiment of an oil-floatablesskimmer 4 which is segmented 4 a, the outlet weir 5, an outlet pipe 6,and an access riser 7 and manhole cover 8.

FIG. 2B is similar to both FIG. 2 and FIG. 2A; however, it includes theaddition of more than one down pipe 26 affixed below the outlet weir 5through the outlet weir orifice control hole 24. The orientation of thefigure is towards the outlet pipe 6 to demonstrate a near frontal-viewof the flow splitter 2. Other elements of the hydrodynamic separator 10depicted include: a top 11 and a bottom 12 and top opening 13, a sumpchamber 3, an inlet pipe 1, a flow splitter 2, an alternate embodimentof an oil-floatables skimmer 4 which is segmented 4 a, the outlet weir5, an outlet pipe 6, and an access riser 7 and manhole cover 8.

FIG. 3 is similar to FIGS. 1 and 2 with the exception of presenting anorientation towards the inlet pipe 1 to demonstrate a near frontal-viewof the outlet weir 5. Other elements of the hydrodynamic separator 10depicted include: a top 11 and a bottom 12, a sump chamber 3, an inletpipe 1, a flow splitter 2, an oil-floatables skimmer 4, an outlet weir5, an outlet pipe 6, and an access riser 7 and manhole cover 8.

FIG. 3A, while similar to FIG. 3, presents a preferred embodiment with adown pipe 26 affixed to the outlet weir 5. The orientation of thisfigure is towards the inlet pipe 1 to demonstrate a near frontal-view ofthe outlet weir 5. Other elements of the hydrodynamic separator 10depicted include: a top 11 and a bottom 12, a sump chamber 3, an inletpipe 1, a flow splitter 2, an oil-floatables skimmer 4, an outlet weir5, an outlet pipe 6, and an access riser 7 and manhole cover 8.

FIG. 3B, while similar to FIGS. 3 and 3A, presents a preferredembodiment with more than one down pipe 26 affixed to the outlet weir 5.The orientation of this figure is towards the inlet pipe 1 todemonstrate a near frontal-view of the outlet weir 5. Other elements ofthe hydrodynamic separator 10 depicted include: a top 11 and a bottom12, a sump chamber 3, an inlet pipe 1, a flow splitter 2, anoil-floatables skimmer 4, an outlet weir 5, an outlet pipe 6, and anaccess riser 7 and manhole cover 8.

FIG. 4 is a top-view of the sump chamber 3 in operation, whereinstormwater enters the sump chamber 3 through the inlet pipe 1 where thestream splits into two opposing streams of water once it reaches theflow splitter 2 and is directed along the walls 14 of the hydrodynamicseparator toward the oil-floatables skimmer 4. The dual swirls of watertravel along the oil-floatables skimmer 4, towards the center of thesump chamber 3 and then back towards the inlet pipe 1 where thesestreams hit the wall of the flow splitter 15 (best seen in FIG. 7) andare directed back toward the side openings of the flow splitter 16 (bestseen in FIG. 7), entering the sump chamber 3 via the inlet pipe 1. Thisaction increases the flow path and it slows the velocity as water movesthrough the hydrodynamic separator 10 and directs finer sediments thatstart to settle downward in the water column underneath the inlet pipe 1below the flow splitter 2. The swirling flow from the inlet on thesurface 30 creates slower velocities, thereby allowing for increasedsettling of finer sedimentation suspended within the stormwater. Removedsettlement will collect at the bottom of the sump chamber 3 of thehydrodynamic separator's floor 12 (not show, see FIG. 1).

FIG. 4 also demonstrates the flow of exiting water on the other side ofthe oil-floatables skimmer 4 wherein treated stormwater travels over thelong top horizontal plane of the outlet weir 5 (best viewed in FIG. 8).This flow direction is demonstrated by laminar flow over the outlet weir31. The top horizontal plane of the outlet weir 5 also serves as a flowdissipation weir to distribute in a laminar fashion to minimizevelocity, further slowing the flow, thus allowing for final treatmentfor fine sediment to settle out before passing up and over the outletweir 5 to the outlet pipe 6.

FIG. 5 demonstrates the typical flow path within the hydrodynamicseparator hydrodynamic separator 10 from a side view perspective. Theprincipal elements responsible for directing water flow, include the:inlet pipe 1, flow splitter 2, sump chamber 3, oil-floatables skimmer 4,and the outlet weir 5 and the outlet pipe 6. The water flow path beginsas a swirling flow from inlet on the surface 30. Then there is a secondswirling motion subsurface 32 action in the lower, open section of thesump chamber 3. Further elements illustrated include the top 11 and abottom 12 and top opening 13 of the hydrodynamic separator 10.

FIG. 6 demonstrates a top-view of the sump chamber 3 with the walls ofthe hydrodynamic separator chamber. While not depicted in FIG. 6, theswirling motion of water flowing through the hydrodynamic separatorsystem 10, can be see in FIG. 5.

FIG. 6A builds on FIG. 6 wherein a secondary swirling motion 32 of fluidmoving through the hydrodynamic separator system 10 is illustrated bythe arrows where the fluid is moving along the subsurface. This movementis capsulated within the walls of hydrodynamic separator chamber 14 ofthe sump chamber 3.

FIG. 6B further develops FIG. 6 and FIG. 6A with a top-view of moreelements of the hydrodynamic separator 10. Water flows in through theinlet pipe 1, is encapsulated by the hydrodynamic separator chamberwalls 14 and exits through the outlet pipe 6. The top-view also includesthe flow splitter 2, oil-floatables skimmer 4, sump chamber 3, and theoutlet weir 5. It also demonstrates the top view of outlet weir orificecontrol holes 24 which may be left open, or in a preferred embodiment,may include down pipes 26 attached directly below (not shown).

FIGS. 5-6B present the multi-filtration process of the hydrodynamicseparator 10 utilizing the flow splitter 2, oil-floatables skimmer 4,down pipe holes 27 and pipes 26, and the outlet weir 5, wherein waterthat was directed at surface water level back toward the inlet pipe 1under the flow splitter 2 comes into contact with the walls 14 of thehydrodynamic separator 10 at which point the water velocity hits thewall 14 and the flow path is once again split in two directions alongthe walls 14 and then flows in two semi-circles toward the outlet pipe 6side of the sump chamber 3 which once again maximizes flow path andallows for more time for sediments to settle to the bottom of the sumpchamber 3. This flow path best illustrates the second swirling motion inthe subsurface 32.

FIG. 7 presents an embodiment of the flow splitter 2 having two sidemounts 18 and bottom mount 17 to be fixed on the walls 14 of thehydrodynamic separator 10 (neither of which are shown). The bottom shelf19 of the flow splitter is connected to the flow splitter wall 15 whichhas openings 16 on its ends to allow water to flow out of the flowsplitter 2. The flow splitter openings 16 provide a gap between the flowsplitter 2 and the hydrodynamic separator walls 14 (not shown) whichenables trash and debris to enter the inlet pipe 1 (not shown) side ofthe sump chamber 3 (not shown), preventing the flow splitter 2 frombecoming clogged. The floatable trash, debris and hydrocarbons arecaught and retained behind the oil-floatables skimmer 4 (not shown)which prevents these pollutants from leaving the hydrodynamic separator10 (not shown).

FIG. 8 presents an embodiment of the outlet weir 5 having two sidemounts 21 to be removably affixed to the perimeter of the sump chamber 3walls along with the bottom mount 20. The outlet weir 5 with a shelf 22extending away from the outlet pipe 6 (not shown) with the opposed endconnected to an outlet weir wall 23 that extends up from the shelf 22.The outlet weir 5 may contain an optional set of orifice control holes24 to control lower flow through the hydrodynamic separator 10.

FIG. 8A similar to FIG. 8; however, it includes the addition of morethan one down pipe 26 affixed below the outlet weir 5 through the outletweir orifice control hole 24. As with FIG. 8, FIG. 8A also includes theoutlet weir 5 with a shelf 22 extending away from the outlet pipe 6 (notshown) with the opposed end connected to an outlet weir wall 23 thatextends up from the shelf 22. The outlet weir 5 may contain an optionalset of orifice control holes 24 to control lower flow through thehydrodynamic separator 10.

FIG. 9 presents an embodiment of the oil-floatables skimmer 4. Theoil-floatables skimmer 4 has a dual function. First it serves as abarrier separating the sump chamber 3 into two sides. The oil-floatablesskimmer 4 neither reaches to the top of the hydrodynamic separator 11(not shown, best seen in FIG. 1) nor the bottom of the hydrodynamicseparator 12 (not shown, best seen in FIG. 1). The oil-floatablesskimmer 4 may have an approximate thickness of 0.1 inches to 3 feet. Thewidth of the oil-floatables skimmer 4 extends across the full width ofthe hydrodynamic separator's diameter from wall 14 to opposite wall 14,where it is removably mounted to said walls with side mounts 25. Theoil-floatables skimmer 4 is positioned vertically so its bottom extendsinto the sump chamber below the invert of the outlet pipe 6 and its topextends above the sump chamber 3 (not shown, best seen in FIG. 1).

The oil-floatables skimmer 4, best seen in FIG. 9, also serves as a weirwhere oils and grease are captured and retained from passing stormwater.Oil and grease removal levels reach up to ninety-nine percent in thepresent invention.

FIG. 9A presents an alternate embodiment of an oil-floatables skimmer 4which is segmented 4 a and outlet weir shelves.

FIG. 10 demonstrates an embodiment of the cleaning of the hydrodynamicseparator 10. In this depiction, a vacuum hose 9, is placed in the sumpchamber 3 on the inlet pipe 1 side of the oil-floatables skimmer 4 Thevacuum hose 9 may be inserted through the manhole cover 8 (not shown,best seen in FIG. 1), via the access riser 7 to remove settled trash anddebris from the sump chamber 3 bottom, located above the hydrodynamicseparator floor 12. FIG. 10 also demonstrates how the sump chamber 3 hasminimal elements, thereby reducing potential obstructions and increasingthe efficiency of cleaning and maintaining the hydrodynamic separator10. Included in this illustration are other elements of the hydrodynamicseparator 10 including: a sump chamber 3, an inlet pipe 1, a flowsplitter 2, an oil-floatables skimmer 4, an outlet weir 5, an outletpipe 6, and an access riser 7.

FIG. 11 demonstrates another embodiment of the cleaning of thehydrodynamic separator 10. In this depiction, a vacuum hose 9, is placedon the outlet pipe 6 side of the sump chamber 3. The vacuum hose 9 maybe inserted through the manhole cover 8 (not shown, best seen in FIG.1), via the access riser 7. As with FIG. 10, FIG. 11 demonstrates howthe sump chamber 3 has minimal elements, thereby reducing potentialobstructions and increasing the efficiency of cleaning and maintainingthe hydrodynamic separator 10. Also identified are other elements of thehydrodynamic separator 10 including: a sump chamber 3, an inlet pipe 1,a flow splitter 2, an oil-floatables skimmer 4, an outlet weir 5, anoutlet pipe 6, and an access riser 7 and the floor 12 of thehydrodynamic separator 10.

The hydrodynamic separator 10 materials may be selected from a groupconsisting of: metal, plastic, concrete, fiberglass, composite, orother. The flow splitter 2, oil-floatables skimmers 4 and outlet weir 5materials may be selected from a group of non-corrosive materialsincluding but not limited to: metal, plastic, concrete, fiberglass,composite, or other.

In an alternate embodiment, more than one inlet pipe(s) 1 may beconnected to the hydrodynamic separator 10 to accommodate additionalstormwater inflow. Additional inlet pipe(s) 1 are positioned to feedinto the same flow splitter 2 or an additional flow splitter 2 could beadded.

In another embodiment, more than one outlet pipe(s) 6 may be positionedin line with each other to increase the speed at which stormwater exitsthe hydrodynamic separator 10. Additional outlet pipe(s) 6 arepositioned to feed into the same outlet weir 5 or an additional outletweir 5 could be added.

Inlet pipe(s) 1 and outlet pipe(s) 6 may have a diameter ofapproximately 2 inches to approximately 30 feet. The diameter of apreferred embodiment ranges from 6 to 72 inches. Materials for the inletpipe 1 and outlet pipe 6 may be selected from a group consisting of:metal, plastic, concrete, composite, clay or other.

The above specification, examples, and data provide a completedescription of the structure and use of exemplary embodiments.Feature(s) of the different embodiment(s) may be combined in yet anotherembodiment without departing from the recited claims.

What is claimed is:
 1. A hydrodynamic separator assembly configured forinstallation within a stormwater drainage infrastructure, wherein thehydrodynamic separator has substantially circular walls with a top, withone or more access openings, a bottom, an inlet opening and an outletopening, and a sump chamber; wherein said hydrodynamic separator,contains three flow weirs each serving a specific function including aflow splitter with one or more side openings and shelves, anoil-floatables skimmer, and an outlet weir containing one or more downpipes; wherein said flow splitter is attached to a wall of saidhydrodynamic separator, such that water entering via the inlet pipeencounters the said flow splitter and water flow is split outward alongthe walls of the hydrodynamic separator, wherein directed water travelsalong said walls toward the oil-floatables skimmer and said directedwater is directed toward the center of the hydrodynamic separator andthen back toward the flow splitter and continues in two circularmotions, wherein water must flow towards an oil-floatables skimmerbottom, said oil-floatables skimmer with bottom is positioned below theinvert of the outlet pipe and the top is positioned above the invert ofthe outlet pipe so that all water must pass under the oil-floatablesskimmer bottom and in doing so trap floatables, wherein said the waterthat travels under said oil-floatables skimmer, must travel back upwardand pass over the outlet weir to make it to the outlet opening or traveldownward to enter the outlet weir orifice control opening at the bottomof the outlet weir, through the attached down pipe(s), to travel upbypassing the outlet weir to the outlet opening, said outlet weir withhorizontal shelf and wall is adjacent to said wall of hydrodynamicseparator via mounts, and positioned so that the wall of the outlet weiris disposed across the outlet opening, wherein the horizontal shelf hasone or more openings which are connected to one more down pipesextending vertically into the sump chamber, the opposite ends of thedown pipes also being open to accept water, wherein said outlet weirallows water to flow over the said weir wall and or up through the downpipes in different proportions based on the amount of flow through thesystem.
 2. The hydrodynamic separator assembly of claim 1, where theinterior of the sump chamber is minimally obstructed by internalcomponents and having an open area of greater than 65% the totalhorizontal area of the structure for the ease of cleaning.
 3. Thehydrodynamic separator assembly of claim 1, where one or more bypasstroughs extends from the flow splitter to the outlet side of theoil-floatables skimmer, allowing higher flow to go through theoil-floatables skimmer to better retain oils and floatables.
 4. Thehydrodynamic separator assembly of claim 1, wherein the oil-floatablesskimmer contains side mounts for removable mounting of theoil-floatables skimmer across the entire breadth of the sump chamber;wherein the oil-floatables skimmer is mounted below the hydrodynamicseparator top opening and with the mount beginning above installed inletand outlet pipe inverts, extending below the bottoms of and outlet weirshelves; wherein the top height of the oil-floatables skimmer is abovethe hydraulic grade line.
 5. The hydrodynamic separator assembly ofclaim 1, wherein the outlet weir is configured to provide an elongatedhorizontal plane diversion for treated stormwater to flow over the top;wherein the outlet weir is comprised of a wall with two side mounts,where the side mounts extend the length of the wall; wherein the walland side mounts connect seamlessly to a curved weir shelf; wherein saidcurved weir shelf has one or more down pipes extending verticallydownward below the level of the bottom of the oil-floatables skimmer;wherein the outlet weir assembly of wall, side mounts, shelf, and downpipes are affixed to a curved bottom mount configured to be flush withthe invert curve of the inside of the sump chamber below the bottom ofan outlet pipe.
 6. The hydrodynamic separator assembly of claim 1,wherein casing of the assembly is selected from the group consisting of:metal, plastic, concrete, fiberglass, composite, and a combinationthereof.
 7. The hydrodynamic separator assembly of claim 1, wherein theflow weirs are selected from a group consisting of: non-corrosivematerials including: metal, plastic, concrete, fiberglass, composite,and a combination thereof.
 8. The hydrodynamic separator assembly ofclaim 1, wherein the inlet and outlet pipes is selected from a groupconsisting of: metal, plastic, concrete, clay, or a combination thereof.9. The hydrodynamic separator assembly of claim 1, wherein the overallsize of the system has a diameter of 2 feet to 100 feet.
 10. Thehydrodynamic separator assembly of claim 1, wherein the inlet and outletpipes have a diameter of 2 inches to 30 feet.
 11. The hydrodynamicseparator assembly of claim 1, wherein the oil-skimmer floatables has athickness of 0.1 inches to 3 feet.
 12. The hydrodynamic separatorassembly of claim 1, wherein during periods of high flow, stormwaterwill be treated wherein entering water passes over the flow splitterwithout passing over the oil-floatables skimmer, exiting over the outletweir and through the outlet pipe.
 13. The hydrodynamic separatorassembly of claim 1, wherein the flow weirs are selected from a groupconsisting of: flow splitters, oil-floatables skimmer, and outlet weirsand a combination thereof.